1. Field of the Disclosure
The present disclosure relates to an instant trip device of a circuit breaker, and particularly, to an instant trip device of a circuit breaker, which can secure a reliability of an instant operation and reduce the cost.
2. Background of the Disclosure
Generally, breaker circuits are a type of electronic device that manually switches on or off an electric circuit by using a handle, or when a fault current such as a short circuit current occurs, detects the fault current to automatically break the electric circuit, thereby protecting a load device and the electric circuit.
FIG. 1 is a cross-sectional view illustrating a relate art circuit breaker. FIG. 2 is a main cross-sectional view illustrating an instant trip device and a crossbar of FIG. 1. FIG. 3 is a perspective view illustrating an assembly process of the instant trip device of FIG. 3. FIG. 4 is a perspective view illustrating an assembly completion state of FIG. 3.
As illustrated in FIGS. 1 to 4, the related art circuit breaker includes a case 10, a fixed contact 20 that is fixedly disposed at the case 10, a moving contact 30 that is disposed to be contactable with and detachable from the fixed contact 20, a switching mechanism 40 that switches on or off the moving contact 30, and an instant trip device 60 that, when a fault current such as a short circuit current occurs, detects the fault current and automatically triggers the switching mechanism 40 in order for the switching mechanism 40 to move to a tripping position within a momentary time. A handle 50 is further provided in an upper region of the case 10 so as to manually switch on or off the switching mechanism 40.
The instant trip device 60 includes a magnet 62 that generates a magnetic absorbing force in exciting, an armature 66 that is disposed at one side of the magnet 62 and is absorbed by the magnet 62, a supporter 64 that rotatably supports the armature 66 at an opposite side of the magnet 62 with respect to the armature 66, and an armature spring 68 that applies an elastic force in a direction where the armature 66 becomes farther away from the magnet 62.
The armature 66 includes a first moving plate 66a and a second moving plate 66b that is bent to be approximately vertical to the first moving plate 66a. The second moving plate 66b includes a shaft hole 66d into which a shaft 69 is inserted.
The supporter 64 includes a first fixed plate 64a and a second fixed plate 64b that is bent to be approximately vertical to the first fixed plate 64a. The second fixed plate 64b includes a shaft supporting part 64c that rotatably supports the armature 66. A shaft inserting hole 64d, into which the shaft 69 is inserted, is formed at the shaft supporting part 64c. 
The armature spring 68 is a double torsion spring, and a coil 68d passes through the armature spring 68 by the shaft 69. One end of the armature spring 68 is supported by the supporter 64, and the other end is supported by the armature 66.
A crossbar 71, a trip shooter 73, a trip bar 75, and a latch holder 77 are provided at one side of the armature 66. When the armature 66 is rotated by the magnet 62, the crossbar 71, the trip shooter 73, the trip bar 75, and the latch holder 77 perform a function (a trigger function) of binding a latch (not shown) of the switching mechanism 40 and releasing the binding of the latch.
Due to such a configuration, when a fault current flows through the magnet 62, the magnet 62 is magnetized to generate a magnetic absorbing force. When the magnetic absorbing force is greater than a weight of the armature spring 68, the armature 66 is absorbed to the magnet 62 side, and is rotated. When the armature 66 is rotated to rotate the crossbar 71, the trip shooter 73, the trip bar 75, and the latch holder 77 are continuously rotated to bind the latch (not shown) of the switching mechanism 40 and release the binding of the latch. When the binding of the latch (not shown) is released, the moving contact 30 is quickly detached from the fixed contact 20 by an elastic force of a trip spring (not shown) of the switching mechanism 40.
However, in the instant trip device 60 of the related art circuit breaker, the shaft inserting hole 64d of the supporter 64, the shaft hole 66d of the armature 66, and the coil 68d of the armature spring 68 are disposed in one row on the same axis, and the shaft 69 is inserted to pass through the elements, whereby the instant trip device is assembled. For this reason, an assembly process is complicated, causing a reduction in assemblability.
Moreover, in the related art instant trip device 60, a problem of scattering, a problem of distortion, and a problem of obstructing a movement of the armature are caused by an accumulation tolerance between the shaft inserting hole 64d of the supporter 64, the shaft hole 66d of the armature 66, the coil 68d of the armature spring 68, and the shaft 69. For this reason, a reliability of an instant operation is reduced.
Moreover, in the related art instant trip device 60, the shaft 69 deviates from a normal position when an element is moved and kept.
Moreover, in the related art instant trip device 60, the number of elements increases due to the separate use of the shaft 69, and the cost increases due to the use of an expensive double torsion spring.